Robust Wideband Aircraft Altitude Estimation for Over-the-Horizon HF Radar

Award Information
Agency: Department of Defense
Branch: Air Force
Contract: FA9453-10-C-0019
Agency Tracking Number: F083-184-1270
Amount: $730,814.00
Phase: Phase II
Program: SBIR
Awards Year: 2010
Solicitation Year: 2008
Solicitation Topic Code: AF083-184
Solicitation Number: 2008.3
Small Business Information
STRAD Corporation
3612 Shannon Road, Suite 200, Durham, NC, 27707
DUNS: 827013470
HUBZone Owned: N
Woman Owned: N
Socially and Economically Disadvantaged: N
Principal Investigator
 Granger Hickman
 Research Scientist
 (919) 660-5419
 gh@stradcorp.com
Business Contact
 Robert Lontz
Title: Chief Administrative Offi
Phone: (919) 475-7916
Email: rl@stradcorp.com
Research Institution
N/A
Abstract
Robust altitude estimation for over-the-horizon radar (OTHR) requires a combination of advanced signal processing and high fidelity ionospheric propagation modeling. Since aircraft height is manifested in closely-spaced direct and ground-bounce reflections off the target, during Phase I, we have developed two new approaches for discriminating small delay differences from a sequence of radar dwells. Both methods exploit wideband frequency-hopped illumination. The first performs maximum a posteriori probability altitude estimation by modeling the frequency-selective fading of the target amplitude-range-Doppler peak. In the second approach, multiband chirp synthesis is used to stitch together dwells so as to resolve small multipath delay differences using a larger effective bandwidth signal. A robust maximum likelihood approach is then applied to map these delay differences to aircraft altitude. In Phase II of this project, we propose to evaluate these methods using operationally-relevant performance metrics and high fidelity ionospheric propagation models which include both ordinary and extraordinary raypaths. In order to study the robustness of our methods, we will also perform Monte Carlo analyses under realistic model mismatch conditions. Finally, existing real OTHR data sets will be identified and a detailed experimental plan will be generated for subsequent full-scale evaluation using a dedicated aircraft. BENEFIT: The development of robust altitude estimation for over-the-horizon (OTH) HF radar would represent a major breakthrough in wide area air surveillance. In addition, we foresee scaling of these techniques to several small-system commercial scenarios. An example is a family of hardware and software modules for a Wide-Area Wi-Fi Radar Intruder Detection System.

* information listed above is at the time of submission.

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